The U.S. Patent and Trademark Office has granted Apple U.S. Patent No. 8,749,380— "Shoe wear-out sensor, body-bar sensing system, unitless activity assessment and associated methods"—which in fact brings together a bunch of fitness-related ideas. But the main point of interest is where the patent explains how a device could be attached to a weightlifting bar to count reps, displaying the result on a watch for remote readings. That'll be an iWatch, then! AppleInsider explains:

[T]he bar device can incorporate Hall Sensors, accelerometers, processors and its own onboard display. Alternatively, number crunching and display duties can be offloaded wirelessly to a user's watch... [A] user can read their workout metrics from the sensor device or a wrist-worn watch. Metrics like time intervals between movements are compared against predetermined data to count reps that are then fed to the watch display for easy reading. A user's reps can be further collected and analyzed by the watch device to track progress over multiple sessions.

Neat! Of course, a patent doesn't mean that Apple will provide such a system, nor that it's going to release an iWatch any time soon. But the sensor does dovetail nicely with Apple's latest health focus and it's worth pointing out that, while we have no idea what an iWatch might look like, there's enough rumor swirling out there that we can totally imagine life with one. We'll just have to wait see if, or when, it actually materializes. [USPTO via Apple Insider]